docs: def from_backend(self, dagobah_id):
          """ Reconstruct this Dagobah instance from the backend. """
          logger.debug('Reconstructing Dagobah instance from backend with ID {0}'.format(dagobah_id))
          rec = self.backend.get_dagobah_json(dagobah_id)
          if not rec:
              raise DagobahError('dagobah with id %s does not exist '
                                 'in backend' % dagobah_id)
          self._construct_from_json(rec)